C++ is one of the most popular Object-Oriented Programming languages used by developers to design and build software and applications. C++ interview questions are asked extensively in technical interviews at FAANG and Tier-1 companies. The language goes way back to 1985, when it was first introduced, and can still perform advanced programming tasks.
If you are preparing for your upcoming technical interview and want to use C++ as your choice of programming language, knowing answers to the commonly asked C++ interview questions is essential. Questions asked at C++ interviews can be around programming theory and coding problems on Data Structures and Algorithms. So in this article, we’ll look at C++ interview questions and answers on programming theory, C++ coding interview questions, basic and C++ interview questions, and more.
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Let’s go ahead and look at some popular C++ interview questions and answers for freshers and experienced developers to help you prepare for your upcoming interview.
Here’s what we’ll discuss:
This is a common C++ interview question asked at software developer interviews. Both C and C++ have similar Syntaxes and code structures, but C++ allows developers to perform more advanced tasks and build comprehensive software programs. While C is a Procedural Oriented Programming Language, C++ is an Object-Oriented Programming Language, thereby incorporating more advanced features. C++ is essentially a superset of C and was developed to address the limitations of C.
Let’s quickly look at the main differences between both these languages.
In this section, we’ll look at some common and popularly asked C++ interview questions that you can expect at your next technical interview.
A Class in C++ is a data type defined by the user. It is a fundamental data type in C++ that defines the behavior and attributes of the entity.
An Object in C++ is an instance of a class. It is an entity that exhibits behavior and state, defined by the Class that it is part of.
There are four different data types in C++. They are:
This is a popular C++ interview question asked in software engineer interviews. The advantages of C++ are:
This is another popular C++ interview question asked at software engineering interviews. C++ is fundamentally Object-Oriented Programming (OOP). The OOP concepts that C++ exhibits include are:
Inheritance is a feature in C++ that allows the reusability of functions in a class, thereby preventing code redundancy. It is a core feature of the Object-Oriented Programming model. Through inheritance, a new class is enabled to inherit the characteristics of an older class. When this happens, the new class is called the Derived Class, while the new class is called the Base class.
This is a standard C++ interview question in C++ software developer interviews and FAANG+ software engineer interviews. Encapsulation is a core feature in C++ that binds the data members and functions in a single unit. Data and information within the class are wrapped and made visible when a request is sent. External methods are prevented from accessing the data within the class through encapsulation.
Abstraction is a core feature in C++ that allows developers only to show the required details while hiding the details on the implementation. If the members of a class are public, they are visible and accessible by external methods and functions.
Polymorphism is a feature in which multiple functions have the same definition but can perform different functionalities. Static polymorphism and dynamic polymorphism are the two types of polymorphism in C++.
In C++, method overloading is a technique through which multiple functions can have the same name but perform different actions. Method overloading in C++ is dependent on the following aspects:
A namespace is a provision in C++ to prevent naming conflicts while running batches of code. Namespace removes the ambiguity in task execution, where different tasks can sometimes run with the same name.
C++ has a standard Namespace called “std,” and various classes, functions, and methods are contained within the Namespace.
The difference between delete and delete commands in C++ is that delete is used to remove a unit of memory in a class, delete is used to remove an entire array.
This gain is a common C++ interview question asked in developer interviews. Access specifiers in C++ declare how functions and class variables contained within a class are accessed. There are three fundamental access specifiers in C++. They are:
You can export a function from DLL by:
A friend function in C++ is a function type that behaves as a friend of a given class and can access the protected and private members (functions and variables) of the class. A friend function isn’t a member of the class in question, but it needs to be specified in the class definition.
This is another common C++ interview question asked in technical interviews. Some characteristics of the friend function include:
Data Binding is a core feature in C++ that allows developers to bind the business logic and application UI. If any changes are made to the program’s business logic, the same will reflect in the application UI.
Arrays and lists are common data types used in Object-Oriented Programming to build software programs and applications. The fundamental difference between the two Arrays is a collection of homogeneous elements, while lists are a collection of heterogeneous elements.
Additionally, the memory allocation for arrays is continuous and static, while the memory allocation for lists is random and dynamic.
A Virtual Function in C++ is fundamentally a member function present in the base class and defined by the derived class. When a function in C++ is virtual, the program decides when the function must be called, depending on the type of the object pointed by the base pointer. C++ can execute different versions of a virtual function.
This is another common C++ interview question asked in technical interviews. Overloading in C++ is when a particular object of a class exhibits multiple behavioral features. The object, during overloading, returns different versions of the function.
The two types of overloading are Function Overloading and Operator Overloading.
While it is possible to call an inline function in C++, the compiler won’t generate the code without a good optimizer. That way, you’re able to execute both recursive and non-recursive functions depending on the depth of recursion.
This again is one of the most popular C++ interview questions asked at technical interviews. The “this” pointer contains the memory address of the given object. Passed in the form of a hidden argument, the “this” pointer is a constant pointer available as a local variable in the body of nonstatic functions.
Operator Overloading is a feature that allows developers to redefine the way an operator functions for user-defined data types. Function Overloading is a feature that enables different functions that exhibit different parameters and behaviors to possess the same name.
Another popular C++ interview question asked at technical interviews pertains to destructors and constructors. In C++, destructors are member functions within the class and possess the same name as the class. Destructors are exhibited automatically when objects lose their scope.
Constructors are special member functions within a class that doesn’t have return types. They are used to initialize new objects of a class. Constructors in C++ are called automatically when objects are created in a class.
Static member functions and static member data are contained within a class and must be declared. When a function is declared static, only a single copy of the data is maintained for the class. Static functions in the class don’t contain the “this” pointer.
In C++, a pure virtual function does not have a formal definition in a class. Pure virtual functions in C++ are succeeded by a “0”.
Scope Resolution operators, specified by the symbol - (::), are fundamentally used to define member functions outside of the class. They come into use when creating protected and private classes in C++.
This again is one of the most common C++ interview questions asked at software developer interviews. Class templates are generally used while creating a family of classes and functions. For instance, while creating an array class, you can create a template to help create various array types such as float, int, etc. Similarly, you can create function templates to define similar functions.
The above C++ interview questions and answers will give you a fair understanding of the concepts that feature in C++ developer and software engineer interviews.
In technical interviews, you will have to attempt coding interview questions around core data structures and algorithms. In fact, in the technical Phone Screen and On-site rounds of tech interviews, your problem-solving skills are tested through the extent of your knowledge and understanding of concepts in core data structures and algorithms.
In this section, we’ll look at some sample C++ coding interview questions asked at FAANG+ interviews.
Before that, here are the topics that are important from the perspective of the interview:
Let’s look at some sample C++ coding interview questions:
If you want to check out more C++ coding interview questions (problems) along with solutions to practice for technical interviews, check out our Problems Page.
If you’re looking to get started with your C++ interview preparation, this section will give you some important tips to answer C++ interview questions effectively and ace your upcoming interview. Here are some tips that will help you with your prep.
Q1. What is C++, and what is it used for?
C++ is a popular general-purpose programming language that allows developers to build scalable user interfaces, software programs, and applications.
Q2. In which interviews C++ interview questions are asked?
You can expect C++ interview questions in C ++developer interviews and coding interviews at FAANG+ companies.
Q3. Do you need in-depth knowledge of C++ to crack technical FAANG interviews?
Knowing your way around how C++ works is vital if you’re choosing C++ as your choice of language. At FAANG interviews, you need to be good with at least one Object-Oriented programming language to solve problem-styled questions in core data structures and algorithms.
Q4. What are some C++ concepts on which tech interview questions are asked?
Some common concepts around which you’re asked C++ interview questions at tech interviews are methods, events in C++, lists, inheritance, polymorphism, abstraction, data binding, and commands used in C++.
Q5. Do you need to answer C++ interview questions to ace design interviews at FAANG+ companies?
Knowing the core concepts in C++ is crucial to ace design interviews at FAANG+ companies. Concepts like inheritance and polymorphism, among others, are extensively used to build scalable applications and systems.
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